Alternative radiator
Discussion
For a while I've been looking around for an alternative radiator for the 350i; firstly because the original Range Rover one has seen better days and secondly because I want to get a route for a cold air duct into the engine air intake. I can monitor the temperature of the air entering the engine on the megasquirt system and it's alarmingly high for most of the time.
I'm thinking that a modern aluminium radiator will be more efficient than the Range Rover one so can be narrower; and then allow me to put the air filter in front of the radiator and run a duct back to the plenum inlet.
I've homed in on the radiator for the Ford Mondeo diesel; which appears to be the same as the one for the ST220 Mondeo - if it's good enough for a 220 hp V6 towing a caravan up the Alps it should be good for a Rover V8. The inlet/outlet/vent connects are similar:
It fits in the nose cone:
And gives me a healthy gap at the side to run a cold air feed:
Dirt cheap too; and comes with a suitable fan and fan shroud.
The hose connections line up well however they are 'quick connects' not conventional hose spiggots so I'll have to be creative and use sections of the original Ford hoses.
Next step is to make up some support brackets; that shouldn't be too difficult as there's two vertical bits of plywood in the nose that allow me to put brackets wherever I need to.
I'm thinking that a modern aluminium radiator will be more efficient than the Range Rover one so can be narrower; and then allow me to put the air filter in front of the radiator and run a duct back to the plenum inlet.
I've homed in on the radiator for the Ford Mondeo diesel; which appears to be the same as the one for the ST220 Mondeo - if it's good enough for a 220 hp V6 towing a caravan up the Alps it should be good for a Rover V8. The inlet/outlet/vent connects are similar:
It fits in the nose cone:
And gives me a healthy gap at the side to run a cold air feed:
Dirt cheap too; and comes with a suitable fan and fan shroud.
The hose connections line up well however they are 'quick connects' not conventional hose spiggots so I'll have to be creative and use sections of the original Ford hoses.
Next step is to make up some support brackets; that shouldn't be too difficult as there's two vertical bits of plywood in the nose that allow me to put brackets wherever I need to.
Yep, That's the idea behind going into the nosecone. A possible option to get cold air is to go straight down from the AFM inlet and pick up air from near the crossmember, but that's almost certain to pull in water.
I'm not going for a ram air effect as firstly it'll ingest rain/dust and secondly the actual ram air effect at normal road speeds isn't significant when compared to the velocity of the air being sucked in by the engine and the pressure losses elsewhere in the system. I'm trying to get the inlet ahead of the radiator, high up in the nosecone, offset from the scoop formed by the spoiler.
I'm not going for a ram air effect as firstly it'll ingest rain/dust and secondly the actual ram air effect at normal road speeds isn't significant when compared to the velocity of the air being sucked in by the engine and the pressure losses elsewhere in the system. I'm trying to get the inlet ahead of the radiator, high up in the nosecone, offset from the scoop formed by the spoiler.
Making progress... made a frame to mount the radiator:
I've had issues making the diesel fan work as it's a variable speed fan controlled by the Ford ECU, so I bought a Mondeo petrol fan/rad assy for £20; that has a conventional fan that I can connect straight to a temp sensor and relay. It's actually a two speed fan so I might connect the low speed to the sensor and the high speed to a dash switch if/when I start to panic about engine temp! I will beef up the TVR wiring though, as it seems to be a powerful fan judging by the Ford wiring cross sectional area. The petrol fan is slightly smaller as well so it will give me more space in the nosecone:
I did consider using the petrol radiator as well, as it has conventional hose spigots; until I realised it's about 5mm less 'deep' than the diesel version.
I've had issues making the diesel fan work as it's a variable speed fan controlled by the Ford ECU, so I bought a Mondeo petrol fan/rad assy for £20; that has a conventional fan that I can connect straight to a temp sensor and relay. It's actually a two speed fan so I might connect the low speed to the sensor and the high speed to a dash switch if/when I start to panic about engine temp! I will beef up the TVR wiring though, as it seems to be a powerful fan judging by the Ford wiring cross sectional area. The petrol fan is slightly smaller as well so it will give me more space in the nosecone:
I did consider using the petrol radiator as well, as it has conventional hose spigots; until I realised it's about 5mm less 'deep' than the diesel version.
The first frame I built was too bulky, so I had to rethink and make it fit much more tightly around the radiator:
It's a pretty tight fit but looks like it will do the job. I wanted to keep the original Ford mounting rubbers to allow heat expansion so the mounting points are large holes.
I've been lucky with the Ford quick connections, they're moulded onto the hoses but I cut the hoses off and found nice barbed connections underneath so I can mount a conventional hose quite easily.
It even looks like I'll be able to use the original swan neck. Looks promising now, I just need to connect it all up...
It's a pretty tight fit but looks like it will do the job. I wanted to keep the original Ford mounting rubbers to allow heat expansion so the mounting points are large holes.
I've been lucky with the Ford quick connections, they're moulded onto the hoses but I cut the hoses off and found nice barbed connections underneath so I can mount a conventional hose quite easily.
It even looks like I'll be able to use the original swan neck. Looks promising now, I just need to connect it all up...
Got the top and bottom hoses connected now, they went on surprisingly well, anyone would think it was designed that way!
Fan wiring next; it appears that the Ford fan can draw more than 30A on start up so I need to put some heavy duty wiring in there. There isn't a sensor in the rad so I have several choices; I'll probably trigger the low speed from Megasquirt based on the ECU engine temp sensor, then have a manual over-ride to put the fan on high speed from a dash mounted switch - I'm thinking I'll wire the dash mounted switch via a permanent live so that I can run the fan with the engine switched off to prevent hot starting problems.
Fan wiring next; it appears that the Ford fan can draw more than 30A on start up so I need to put some heavy duty wiring in there. There isn't a sensor in the rad so I have several choices; I'll probably trigger the low speed from Megasquirt based on the ECU engine temp sensor, then have a manual over-ride to put the fan on high speed from a dash mounted switch - I'm thinking I'll wire the dash mounted switch via a permanent live so that I can run the fan with the engine switched off to prevent hot starting problems.
I've got the air intake in place now and it's looking pretty good; although the duct I bought was 1m long and is still a little short, I could do with having the air filter further forward and also a more gentle curve onto the plenum.
It'll do for now while I sort the rest out. I need to refit the front spoiler; I'm expecting to have to shave some material off the air intake to accomodate the new radiator.
I still need to sort out the fan wiring, it blows a 25A fuse when switched on to high speed (low speed is OK) so I'm pondering a need for high current relays, standard ones are 30A but it's possible to buy 70A ones. I also appear to have damaged the alternator as I'm seeing 20 Volt spikes on the power supply to the ECU - unsurprisingly the ECU is not happy! I suspect I have something going on with the fans, perhaps when they switch off... ho hum.
It'll do for now while I sort the rest out. I need to refit the front spoiler; I'm expecting to have to shave some material off the air intake to accomodate the new radiator.
I still need to sort out the fan wiring, it blows a 25A fuse when switched on to high speed (low speed is OK) so I'm pondering a need for high current relays, standard ones are 30A but it's possible to buy 70A ones. I also appear to have damaged the alternator as I'm seeing 20 Volt spikes on the power supply to the ECU - unsurprisingly the ECU is not happy! I suspect I have something going on with the fans, perhaps when they switch off... ho hum.
Yes, I'll need to squash the pipe to make room for the bonnet as it sweeps down on opening. Plan A is to simply squash the pipe (it's got a coil of soft wire in it so it'll hold it's shape when squashed); I may also have to put something hard around the pipe to protect it from the sliding action as the bonnet pivots in an arc. Plan B is a letterbox shaped duct but I'm hoping I can get away without that - but as you say it does solve the pipe length issue!
I've got the engine running again now, it turns out that the voltage spikes at the ECU were nothing to do with the fans but instead were the effects of the flapper injectors vs the hotwire ones I had before.
Fan current on low speed hits 32Amps on start up so I definitely need high current relays for the high speed setting. Steady state current draw is about 14Amps on low speed - but the airflow from the Ford fan is huge compared to the TVR original even on low speed. Those values were engine off and 11V at the battery so it'll be more with the alternator running. I am wiring it direct to the battery and keeping the leads short. This is a trace of fan voltage and current:
Below is a graph trace from Megasquirt while running the engine on my drive with the bonnet off. It's time in seconds along the bottom so about 23 minutes of engine idling from a cold start. It shows engine coolant temp in green, air intake temp in red and the fan cutting in and out in purple. The initial engine temp fluctuations before the fan cuts in are the thermostat opening, allowing cold coolant in from the radiator circuit.
I had the fan set to come on at 90DegC for the first event then 95 DegC for the second and third times. It shows the air intake temperature increasing when the fan is running so it looks like the hot air is recirculating around the radiator within the nosecone. I suspect I'll have to put baffles around the periphery of the radiator to stop this recirculation but that would also reduce the airflow into the engine bay at speed; so I'll wait until I've driven the car in hot weather before I decide what to do. I'll also try and get the air intake further forward.
One of the problems with megasquirt is it gives you too much information and starts you worrying!
Fan current on low speed hits 32Amps on start up so I definitely need high current relays for the high speed setting. Steady state current draw is about 14Amps on low speed - but the airflow from the Ford fan is huge compared to the TVR original even on low speed. Those values were engine off and 11V at the battery so it'll be more with the alternator running. I am wiring it direct to the battery and keeping the leads short. This is a trace of fan voltage and current:
Below is a graph trace from Megasquirt while running the engine on my drive with the bonnet off. It's time in seconds along the bottom so about 23 minutes of engine idling from a cold start. It shows engine coolant temp in green, air intake temp in red and the fan cutting in and out in purple. The initial engine temp fluctuations before the fan cuts in are the thermostat opening, allowing cold coolant in from the radiator circuit.
I had the fan set to come on at 90DegC for the first event then 95 DegC for the second and third times. It shows the air intake temperature increasing when the fan is running so it looks like the hot air is recirculating around the radiator within the nosecone. I suspect I'll have to put baffles around the periphery of the radiator to stop this recirculation but that would also reduce the airflow into the engine bay at speed; so I'll wait until I've driven the car in hot weather before I decide what to do. I'll also try and get the air intake further forward.
One of the problems with megasquirt is it gives you too much information and starts you worrying!
Edited by The Hatter on Tuesday 24th January 21:27
The car is back on the road now, seems OK so far!
The spoiler went back on without cutting too much off
70Amp relay for the fan fast speed and a 30A for slow...
Battery connection through a race/kit car fuse box; added advantage of all the circuits on the car are now fused (except the starter cable):
Inlet pipe is crushed by the bonnet but I'll monitor it and see if it gets damaged:
Misson accomplished!
The spoiler went back on without cutting too much off
70Amp relay for the fan fast speed and a 30A for slow...
Battery connection through a race/kit car fuse box; added advantage of all the circuits on the car are now fused (except the starter cable):
Inlet pipe is crushed by the bonnet but I'll monitor it and see if it gets damaged:
Misson accomplished!
I might put a flat duct of some sort in there, but I'm conscious of restricting the airflow - the duct that is on there at the moment springs back to a more round shape when I close the bonnet. I'm thinking that I'll just see how it goes; if it tears then I get unfiltered air into the engine, so not too big a deal as long as I look out for it.
That's the one Adam, although you need to make sure you get the rad hoses with their quick connects and all the mounting rubbers. I actually bought a used rad to play around with and get all the pipes/rubbers, then bought a new rad (chinese - £45!) and used that for the final fit up. I'll do a list at some point of exactly what I used.
One word of caution though... the weather isn't hot at the moment and I've yet to give the car a serious work out! Ideally I need to do a high speed run up a hill in hot weather to see what the cooling is like under those conditions.
That's the one Adam, although you need to make sure you get the rad hoses with their quick connects and all the mounting rubbers. I actually bought a used rad to play around with and get all the pipes/rubbers, then bought a new rad (chinese - £45!) and used that for the final fit up. I'll do a list at some point of exactly what I used.
One word of caution though... the weather isn't hot at the moment and I've yet to give the car a serious work out! Ideally I need to do a high speed run up a hill in hot weather to see what the cooling is like under those conditions.
Just to conclude this thread, the car has run all summer with no problems at all including trips to the EVO triangle in North Wales and another trip to the Lake District. It's been driven in torrential downpours and very wet roads with no detrimental water pulled into the intake. It also survived a grass autotest in July on a very hot day, with lots of revs in 1st gear and not alot of forward motion!
https://www.youtube.com/watch?v=6Z6PgE7vKQc
Inlet air temps are a lot lower too so idling in traffic and hot starts are not a problem. A very successful mod, certainly worthwhile. The only downside is having to trim away some of the front spoiler to clear the rad; other than that it's all reversible- if anyone was that way inclined.
https://www.youtube.com/watch?v=6Z6PgE7vKQc
Inlet air temps are a lot lower too so idling in traffic and hot starts are not a problem. A very successful mod, certainly worthwhile. The only downside is having to trim away some of the front spoiler to clear the rad; other than that it's all reversible- if anyone was that way inclined.
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